mysql 8 plugin caching_sha2_password could not be loaded

原因，认证方面问题，使用root登录，执行：

mysql> alter user 'root'@'%' identified by 'Abc#1234' password expire never;
Query OK, 0 rows affected (0.09 sec)

mysql> alter user 'root'@'%' identified with  mysql_native_password by  'Abc#1234';
Query OK, 0 rows affected (0.08 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.04 sec)

mysql>  alter  user 'root'@'%' identified by 'Abc#1234';
Query OK, 0 rows affected (0.05 sec)

官方说明：https://dev.mysql.com/doc/refman/8.0/en/upgrading-from-previous-series.html#upgrade-caching-sha2-password